IS200TRESH2A - Steam Turbine Emergency Trip Board

IS200TRESH2A - Steam Turbine Emergency Trip Board IS200TRESH2A - Steam Turbine Emergency Trip Board

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Part No.: IS200TRESH2A
Manufacturer: General Electric
Product Type: Steam Turbine Emergency Trip Board
Country of Manufacture: United States (USA)
Availability: In Stock
Trip interlock isolation: Optical isolation
Trip interlock filter: Hardware filter, 4 ms
Trip interlock ac voltage rejection: 60 V rms
Size: 7.0 in x 13.0 in
Number of trip solenoids: Three
Series: Mark VI

Functional Description

IS200TRESH2A is a Steam Turbine Emergency Trip Board developed by GE. It is a part of Mark VI control system. TRES, or Turbine Overspeed Protection System, serves as a critical component in ensuring emergency overspeed protection for small to medium-sized steam turbines. Controlled by the I/O controller, TRES plays a pivotal role in safeguarding turbine operations during unforeseen events.

Functionality and Control

  • Emergency Trip Solenoids: It provides power to three emergency trip solenoids, offering a robust mechanism for rapid shutdown in emergency situations. These solenoids can be seamlessly connected between the TRES and TRPS terminal boards, facilitating efficient communication and control.
  • I/O Controller Integration: The I/O controller orchestrates the emergency overspeed protection functions, emergency stop functionalities, and governs the operation of the three relays situated on the TRES. This centralized control mechanism ensures swift and precise responses to critical events, enhancing overall system reliability.

Relay Configuration

  • Absence of Economizing Relays: Unlike some systems, TRES does not feature economizing relays. Instead, its design prioritizes rapid response and emergency shutdown functionalities, ensuring swift and decisive action in critical scenarios.
  • Relay and Monitoring Integration: The board includes essential components such as the synch check relay driver, K25A, and its associated monitoring functionalities, ensuring precise synchronization checks and system integrity. Additionally, the servo clamp relay driver, K4CL, and its monitoring mechanisms are integrated into the board, further enhancing operational safety and reliability.


  • Notably, a second TRES board cannot be driven directly from the I/O controller through J4, emphasizing the standalone nature of each TRES unit within the system architecture. This limitation underscores the importance of careful system planning and configuration to ensure optimal performance and redundancy where needed.
  • TRES is available in both simplex and Triple Modular Redundant (TMR) forms, providing flexibility to suit diverse operational requirements and redundancy needs.
  • Trip Interlocks: With seven dry contact inputs dedicated to trip interlocks, TRES boasts comprehensive monitoring capabilities, enabling real-time assessment of critical parameters and swift initiation of protective measures when necessary.


  • Trip Solenoids Connection: The three trip solenoids are interconnected and wired to the first I/O terminal block. This arrangement ensures streamlined communication and control of these critical components, facilitating rapid response in emergency scenarios.
  • Trip Interlock Wiring: The second terminal block accommodates the wiring for up to seven trip interlocks. These interlocks play a vital role in monitoring various parameters and initiating protective actions when necessary. Proper wiring ensures seamless integration and reliable operation of the TRES system.
  • Connector J2: This connector serves as the conduit for three power buses originating from the TRPS (Turbine Remote Protection System). These buses provide the necessary power supply to the TRES system, ensuring consistent and reliable operation.
  • Connector JH1: Responsible for carrying the excitation voltage required for the operation of the seven trip interlocks. This voltage supply is crucial for enabling the monitoring and activation of trip interlocks, enhancing the overall safety and functionality of the TRES system.
  • Ensuring correct wiring and connection of components is paramount during the installation process. Proper installation not only promotes optimal system performance but also minimizes the risk of operational disruptions and enhances system reliability. By adhering to the prescribed wiring configurations and utilizing the designated connectors, installers can effectively harness the full capabilities of the TRES system, fortifying turbine operations against potential hazards and emergencies.

World of Controls has the most comprehensive collection of GE components. Please contact WOC as soon as possible if you require any extra information.

Frequently Asked Questions

What is IS200TRESH2A?
It is a Steam Turbine Emergency Trip Board developed by GE.

What diagnostics does the I/O controller perform on the TRES board and connected devices?
The I/O controller runs diagnostics covering trip relay driver and contact feedbacks, solenoid voltage, K25A relay driver and coil, servo clamp relay driver and contact feedback, and solenoid voltage source. Any deviation triggers a fault.

What information do connectors JA1, JX1, JY1, and JZ1 provide?
Each connector hosts an ID device with a read-only chip containing terminal board serial number, board type, revision number, and plug location. This information ensures compatibility and integrity of connected components.

How does the I/O controller use information from ID devices on connectors?
Upon interrogation, the I/O controller verifies connector information. A mismatch triggers a hardware incompatibility fault, prompting corrective action to maintain system integrity.

What actions should be taken if a fault is detected during diagnostics or ID device interrogation?
Address faults promptly by inspecting wiring, verifying component integrity, and seeking technical support if needed. Timely resolution ensures reliable system performance.